In the past, movable staircases were used to allow passengers to board and alight an aircraft. Passengers exited an airport terminal and walked along and sometimes across a portion of a fairway or runway. This exposed passengers to outdoor elements and airport traffic as well as requiring them to climb a steep flight of stairs with carry-on baggage. While movable staircases are still used in some airports, they have largely been replaced with Passenger Boarding Bridges.
A Passenger Boarding Bridge (PBB) is an enclosed, movable connector that extends from an airport terminal gate to an airplane, and in some instances from a port to a boat or ship. It allows passengers to board and disembark without going outside or being exposed to the elements. PBBs improve passenger access to aircraft and enhance the security of terminal operations. A PBB may also be known as a jet-bridge, jet-way, gangway, aerobridge/air-bridge, air jetty, portal or sky-bridge.
Depending on building design, sill heights, fueling positions, and operational requirements, a PBB may be fixed or movable. A movable PBB is often attached at one end by a pivot (or rotunda) to the terminal building and has the ability to swing left or right. The cabin, at the distal end of the loading bridge, may be raised or lowered, extended or retracted, and may pivot to accommodate aircraft of different sizes. These motions are controlled by an operator's station in the cab. The cab often has an accordion-like canopy, which allows the bridge to dock with aircraft with differing shapes, and provides a seal from outdoor elements. While the design of PBBs has improved, there are inherent problems with their operation and safety.
A PBB must be operated by a trained employee or member of the airport ground crew, thus requiring manpower that could be used for another function. Usually a ground crew has only a few members who are trained to operate a PBB. A crewman must put other work aside to operate the docking or retraction process. If a trained crewman is not readily available, the passengers and airline crew must wait for one. This can lead to delay in boarding and alighting when multiple aircraft arrive or intend to depart within a short period of time or with inadequate staffing. Even a relatively short delay can cost an airline thousands of dollars in labor and fuel. It can also lead to missed connections and discontent passengers.
The operation of PBBs is also susceptible to human error which can pose dangers and hazards to aircraft. There are several documented cases wherein mistakes by crewman caused damage to an aircraft and PBB. Even with a series of safety checks and operation protocols, workers inevitably make errors due to fatigue, haste and distraction. A PBB can cause millions of dollars in damage if driven into a component of an aircraft or into a foreign object on the fairway. Further, conventional PBBs can be difficult to operate.
Because of limited visibility from the cab, a PBB can be inadvertently driven into a structure or object. Safe docking requires a clear line of sight from the cab to the aircraft door. Precipitation, fog, haze, dust or inclement weather can obstruct the operator's view. In many airports, particularly in large urban environments, haze has become commonplace. Moreover, if a bridge is not fully retracted before departure, it can contact parts of the moving aircraft and cause damage. In may impossible to visually determine whether a PBB is fully retracted in darkness or with poor visibility,
Attempts have been made toward improving PBBs and their operation. For example, U.S. Pat. No. 5,226,204 describes a PBB that includes sensors and a telerobotic control apparatus for aligning the end of the PBB with the door of an aircraft. However, this system can be ineffective during inclement weather and when visibility is poor. Further, it requires the time and attention of a trained ground crewman. U.S. Pat. No. 8,645,004 describes an automated PBB that can be programed to connect with a particular make and model of a plane. However, this system is prone to error and requires accurate data on every make and model of plane that arrives at the terminal. Further, the plane must be precisely positioned for the PBB to connect without misaligning.
Other designs require visual markings on aircraft to identify the location of the passenger door. Such a method is described in U.S. Pat. No. 7,137,162 wherein “targets” are affixed to an aircraft fuselage that are used to guide a passenger bridge into contact with the passenger door. This system is also problematic as the markings are susceptible to lighting conditions and can be obscured in fog, haze or rain. Further, an airport authority would have to outfit all aircraft with these “targets.” Doing so would require all aircraft companies and pertinent regulatory agencies to accept the system. Moreover, the airport would have to maintain conventional PBBs for aircraft that did not have the visual markings.
Because of these limitations, there is a need for an improved PBB docking system. Specifically, there is a need for a fully automated computerized aircraft PBB docking system that is safe and efficient, eliminates human error and is reliable regardless of visibility.